In preparation for removing the strlcat() API[1], replace its uses in the error message construction of the ThunderX OCX and L2C threaded IRQ handlers.
The OCX link and L2C handlers append a single decoded-register string, so the whole message can be produced with one snprintf(). The OCX com handler accumulates a variable number of fragments in a per-lane loop, so use a struct seq_buf, which tracks the current write position and remaining space internally. seq_buf_str() keeps the message NUL-terminated for edac_device_handle_ce(). Link: https://github.com/KSPP/linux/issues/370 [1] Signed-off-by: Ian Bridges <[email protected]> --- The seq_buf conversion introduces one behavioral difference on overflow. strlcat() copied as much of a fragment as would fit, but seq_buf_puts() is all-or-nothing. A message longer than OCX_MESSAGE_SIZE therefore truncates at a fragment boundary instead of mid-fragment. The message was truncated either way. I don't have ThunderX hardware, so I tested the patch with: - arm64 cross-build at W=1 with no warnings. Applies cleanly on v7.2-rc1. - Module load/unload in an arm64 QEMU guest. - A userspace harness comparing old and new message construction; outputs matched across ~500k register patterns. drivers/edac/thunderx_edac.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c index 75c04dfc3962..5210ca18473d 100644 --- a/drivers/edac/thunderx_edac.c +++ b/drivers/edac/thunderx_edac.c @@ -20,6 +20,7 @@ #include <linux/atomic.h> #include <linux/bitfield.h> #include <linux/circ_buf.h> +#include <linux/seq_buf.h> #include <asm/page.h> @@ -1108,6 +1109,7 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id) int lane; char *msg; char *other; + struct seq_buf sb; msg = kmalloc(OCX_MESSAGE_SIZE, GFP_KERNEL); other = kmalloc(OCX_OTHER_SIZE, GFP_KERNEL); @@ -1121,13 +1123,14 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id) ARRAY_SIZE(ocx->com_err_ctx)); ctx = &ocx->com_err_ctx[tail]; - snprintf(msg, OCX_MESSAGE_SIZE, "%s: OCX_COM_INT: %016llx", - ocx->edac_dev->ctl_name, ctx->reg_com_int); + seq_buf_init(&sb, msg, OCX_MESSAGE_SIZE); + seq_buf_printf(&sb, "%s: OCX_COM_INT: %016llx", + ocx->edac_dev->ctl_name, ctx->reg_com_int); decode_register(other, OCX_OTHER_SIZE, ocx_com_errors, ctx->reg_com_int); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&sb, other); for (lane = 0; lane < OCX_RX_LANES; lane++) if (ctx->reg_com_int & BIT(lane)) { @@ -1136,16 +1139,17 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id) lane, ctx->reg_lane_int[lane], lane, ctx->reg_lane_stat11[lane]); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&sb, other); decode_register(other, OCX_OTHER_SIZE, ocx_lane_errors, ctx->reg_lane_int[lane]); - strlcat(msg, other, OCX_MESSAGE_SIZE); + seq_buf_puts(&sb, other); } if (ctx->reg_com_int & OCX_COM_INT_CE) - edac_device_handle_ce(ocx->edac_dev, 0, 0, msg); + edac_device_handle_ce(ocx->edac_dev, 0, 0, + seq_buf_str(&sb)); ocx->com_ring_tail++; } @@ -1203,15 +1207,13 @@ static irqreturn_t thunderx_ocx_lnk_threaded_isr(int irq, void *irq_id) ctx = &ocx->link_err_ctx[tail]; - snprintf(msg, OCX_MESSAGE_SIZE, - "%s: OCX_COM_LINK_INT[%d]: %016llx", - ocx->edac_dev->ctl_name, - ctx->link, ctx->reg_com_link_int); - decode_register(other, OCX_OTHER_SIZE, ocx_com_link_errors, ctx->reg_com_link_int); - strlcat(msg, other, OCX_MESSAGE_SIZE); + snprintf(msg, OCX_MESSAGE_SIZE, + "%s: OCX_COM_LINK_INT[%d]: %016llx%s", + ocx->edac_dev->ctl_name, + ctx->link, ctx->reg_com_link_int, other); if (ctx->reg_com_link_int & OCX_COM_LINK_INT_UE) edac_device_handle_ue(ocx->edac_dev, 0, 0, msg); @@ -1882,14 +1884,12 @@ static irqreturn_t thunderx_l2c_threaded_isr(int irq, void *irq_id) while (CIRC_CNT(l2c->ring_head, l2c->ring_tail, ARRAY_SIZE(l2c->err_ctx))) { - snprintf(msg, L2C_MESSAGE_SIZE, - "%s: %s: %016llx, %s: %016llx", - l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int, - ctx->reg_ext_name, ctx->reg_ext); - decode_register(other, L2C_OTHER_SIZE, l2_errors, ctx->reg_int); - strlcat(msg, other, L2C_MESSAGE_SIZE); + snprintf(msg, L2C_MESSAGE_SIZE, + "%s: %s: %016llx, %s: %016llx%s", + l2c->edac_dev->ctl_name, reg_int_name, ctx->reg_int, + ctx->reg_ext_name, ctx->reg_ext, other); if (ctx->reg_int & mask_ue) edac_device_handle_ue(l2c->edac_dev, 0, 0, msg); -- 2.47.3
